Low-E coating system including protective DLC

ABSTRACT

A substrate is coated with a low-E coating system including at least one infrared (IR) reflective layer. A diamond-like carbon (DLC) inclusive protective coating system (e.g., including at least one highly tetrahedral amorphous carbon (ta-C) inclusive layer having sp 3  carbon-carbon bonds) is provided on the substrate over at least the IR reflective layer in order to make the low-E coating system scratch resistant, abrasion resistant, and generally mechanically durable. The DLC inclusive protective coating system may be hydrophobic, hydrophillic, or neutral in different embodiments of the invention. Optionally, at least one fluoro-alkyl silane (FAS) compound inclusive layer may be provided on the substrate over at least one of the DLC inclusive layer(s) in hydrophobic embodiments in order to increase contact angle θ of the coated article.

[0001] This is a continuation-in-part (CIP) of U.S. patent applicationSer. No. 09/303,548, filed May 3, 1999, and a continuation-in-part (CIP)of U.S. patent application Ser. No. 09/442,805, filed Nov. 18, 1999, anda continuation-in-part (CIP) of U.S. patent application Ser. No.09/583,862 filed Jun. 1, 2000, entitled “Hydrophobic Coating IncludingDLC on Substrate”, and a CIP of U.S. patent application Ser. No.09/617,815, filed Jul. 17, 2000, entitled “Hydrophobic Coating with DLC& FAS on Substrate”, the disclosures of which are all herebyincorporated herein by reference.

[0002] This invention relates to a low emissivity (low-E) coating systemincluding diamond-like carbon (DLC) provided on (directly or indirectly)a substrate of glass, plastic, ceramic, or the like, and a method ofmaking the same.

BACKGROUND OF THE INVENTION

[0003] Sputter coated systems for deposition on glass are known in theart for achieving solar management properties in glass articles such asinsulating glass (IG) windows, vehicle windows, and the like. In manysuch coating systems, it is desirable to provide a coating systemcapable of: (i) reflecting a certain amount of infrared (IR) radiation,while (ii) allowing an acceptable amount of visible light transmittance,and (iii) limiting the amount of visible light reflectance off of thecoating system.

[0004] Exemplary low-E coating systems are disclosed in U.S. Pat. Nos.5,800,933; 5,770,321; 5,419,969; and 5,344,718, the disclosures of whichare all hereby incorporated herein by reference.

[0005] Unfortunately, many conventional low-E coating systems are proneto scratching. Thus, they are not as abrasion resistant as would bedesired. Because of this potential for scratching, many low-E coatingsystems are not typically utilized in applications such as rear vehiclewindows (e.g., back seat vehicle windows, vehicle backlites, etc.).Instead, such windows are often tinted in order to keep IR rays out ofthe vehicle (which also has the effect of reducing visibility in certaincircumstances).

[0006] U.S. Pat. No. 5,976,683 discloses a coating system having hightransmissivity in the visible spectrum and high reflectivity in thethermal radiation spectrum. A polycrystalline carbon layer crystallizedwith a diamond structure and doped with foreign atoms is provided andformed via CVD. Unfortunately, such polycrystalline layers are difficultand expensive to deposit on substrates and typically require very hightemperatures during the deposition process (e.g., from 700 to 1,000degrees C.). If one attempted to elevate a substrate including a low-Ecoating system thereon to such temperatures, many such low-E systemswould be destroyed or significantly damaged. Thus, the use of apolycrystalline diamond layer formed in such a manner over a low-Esystem is neither practical nor desirable.

[0007] In view of the above, it will be apparent to those skilled in theart that there exists a need in the art for an improved scratchresistant and/or mechanically durable low-E coating system for use inautomotive and/or architectural window applications. There also exists aneed in the art for a low-E coating system that can repel water and/ordirt, and a method of making the same. There also exists a need in theart for a low-E coating system including a protective layer(s) systemthat can be deposited over underlying low-E layers via a low temperatureprocess.

[0008] It is a purpose of different embodiments of this invention tofulfill any or all of the above described needs in the art, and/or otherneeds which will become apparent to the skilled artisan once given thefollowing disclosure.

SUMMARY OF THE INVENTION

[0009] An object of this invention is to provide a low-E coating systemthat is scratch resistant and mechanically durable.

[0010] Another object of this invention is to provide a diamond-likecarbon (DLC) inclusive protective layer(s) or coating system locatedover a low-E layer arrangement, wherein the DLC inclusive protectivelayer(s) or coating system can be deposited in or via a low temperatureprocess so as to not significantly damage the existing or underlyinglow-E layer arrangement.

[0011] Another object of this invention is to provide a low-E coatingsystem that is (i) scratch resistant and mechanically durable, (ii)capable of reflecting an acceptable amount of infrared (IR) radiation,(iii) capable of allowing an acceptable amount of visible lighttransmittance, and (iv) capable of limiting the amount of visible lightreflectance off of the coating system.

[0012] While non-hydrophobic low-E coating systems are often desirable,there also sometimes exists a need in the art for a low-E coating systemthat may be hydrophobic (i.e., can shed or repel water) if desired.Thus, another object of this invention is to provide low-E coatingsystems that are hydrophobic, as well as low-E coating systems that neednot be hydrophobic.

[0013] Another object of this invention is to provide a scratchresistant low-E coating system including at least one diamond-likecarbon (DLC) inclusive layer having at least some highly tetrahedralamorphous carbon (ta-C), wherein the ta-C includes sp³ carbon-carbonbonds so as to make the layer more scratch resistant and mechanicallydurable.

[0014] In certain embodiments, a low-E coating system may include eachof a DLC inclusive layer(s) and a fluoro-alkyl silane (FAS) compoundinclusive layer, wherein the DLC is provided for durability purposes andthe FAS for increasing the contact angle θ of the coating system.

[0015] Another object of certain embodiments of this invention is toprovide a low-E coating system including sp³ carbon-carbon bonds andFAS, the low-E coating system having a wettability W with regard towater of less than or equal to about 23 mN/m, more preferably less thanor equal to about 21 mN/m, even more preferably less than or equal toabout 20 mN/m, and in most preferred embodiments less than or equal toabout 19 mN/meter. This can also be explained or measured in Joules perunit area (mJ/m²)

[0016] Another object of this invention is to provide a low-E coatingsystem having a surface energy γ_(C) (on the surface of the coatedarticle) of less than or equal to about 20.2 mN/m, more preferably lessthan or equal to about 19.5 mN/m, and most preferably less than or equalto about 18 mN/m.

[0017] Another object of this invention is to provide a low-E coatingsystem having an initial (i.e. prior to being exposed to environmentaltests, rubbing tests, acid tests, UV tests, or the like) water contactangle θ of at least about 55 degrees, more preferably of at least about80 degrees, still more preferably of at least about 100 degrees, evenmore preferably of at least about 110 degrees, and most preferably of atleast about 125 degrees.

[0018] Another object of this invention is to manufacture a low-Ecoating system including at least one DLC inclusive layer, wherein theDLC inclusive layer is deposited in a manner such that during thedeposition process the underlying substrate and/or IR reflecting layer(e.g., Ag layer) may be kept at temperature(s) no greater than about200° C., preferably no greater than about 150° C., most preferably nogreater than about 80° C., so as to reduce the likelihood ofheat-induced damage to portions of the low-E coating system.

[0019] Yet another object of this invention is to fulfill any and/or allof the aforesaid objects and/or needs.

[0020] This invention will now be described with respect to certainembodiments thereof, along with reference to the accompanyingillustrations.

IN THE DRAWINGS

[0021]FIG. 1 is a side cross sectional view of a coated articleaccording to an embodiment of this invention, wherein a substrate isprovided with a low-E coating system thereon including a DLC inclusiveprotective layer.

[0022]FIG. 2(a) is a side cross sectional view of a coated articleaccording to another embodiment of this invention, wherein a substrateis provided with a low-E coating system thereon including a pair of DLCinclusive protective layers and a FAS compound inclusive layer.

[0023]FIG. 2(b) is a side cross sectional view of a coated articleaccording to another embodiment of this invention, wherein a substrateis provided with a low-E coating system thereon including a pair ofprotective DLC inclusive layers.

[0024]FIG. 3 is a side cross sectional view of a coated articleaccording to another embodiment of this invention, wherein a substrateis provided with a low-E coating system thereon according to any of theFIGS. 1, 2(a) or 2(b) embodiments and an index matching layer isprovided between the substrate and the low-E coating system in order tofurther reduce visible reflections.

[0025]FIG. 4(a) is a side cross sectional partially schematic viewillustrating a low contact angle θ of a water drop on a glass substrate.

[0026]FIG. 4(b) is a side cross sectional partially schematic viewillustrating the coated article of any of the FIGS. 1-3 embodiments(when a hydrophobic system is desired) of this invention and the contactangle θ of a water drop thereon.

[0027]FIG. 5 is a perspective view of a linear ion beam source which maybe used in any embodiment of this invention for depositing DLC inclusivelayer(s) (it is noted that sputtering is a preferred method/techniquefor depositing the layers under the DLC inclusive layer(s)).

[0028]FIG. 6 is a cross sectional view of the linear ion beam source ofFIG. 5.

[0029]FIG. 7 is a diagram illustrating tilt angle as discussed herein inaccordance with certain embodiments of this invention.

[0030]FIG. 8 is a chart illustrating the atomic amounts of carbon,oxygen, and silicon (relative only to one another) at differentthicknesses of the two DLC inclusive layers of the FIG. 2 coating system(i.e., without an overlying FAS inclusive layer).

[0031]FIG. 9 is a chart illustrating the atomic amounts of carbon,oxygen, and silicon (relative only to one another) at differentthicknesses of the FAS portion of a sample coating system in accordancewith the FIG. 2(a) embodiment of this invention; so FIGS. 8-9 can beused together to illustrate a complete coating system including both DLCand FAS inclusive layers of the FIG. 2(a) embodiment.

[0032]FIG. 10 is a flowchart illustrating how the FAS inclusive layer ofthe FIG. 2(a) embodiment may be thermally cured according to anembodiment of this invention.

[0033]FIG. 11 is a graph illustrating certain “n” (index of refraction)and “k” values for certain DLC inclusive layers according to differentembodiments of this invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THIS INVENTION

[0034] Referring now more particularly to the accompanying drawings inwhich like reference numerals indicate like elements throughout theaccompanying views.

[0035]FIG. 1 is a side cross sectional view of a substrate provided witha low-E coating system thereon according to an embodiment of thisinvention. The product includes underlying substrate 1 of glass, ceramicor plastic (preferably soda-lime-silica float glass from about 1.5 to 6mm thick), substantially transparent dielectric layer 2 (e.g., of orincluding silicon nitride, silicon oxynitride, SiO₂, TiO₂, PbO, Bi₂O₃,or any mixture thereof), substantially transparent dielectric layer 3(e.g., of or including a nitride such as silicon nitride having amake-up of approximately Si₃N₄), first metal or metal oxide or metalnitride layer 4 (e.g., of or including Ni, Cr, NiCr, NiCrO_(x),NiCrN_(x) or any mixture thereof), metallic IR reflective layer 5 (e.g.,of or including Ag), second metal or metal oxide or metal nitride layer6 (e.g., of or including Ni, Cr, NiCr, NiCrO_(x), NiCrN_(x) or anymixture thereof), substantially transparent dielectric layer 7 (e.g., ofor including a nitride such as silicon nitride having a make-up ofapproximately Si₃N₄), and diamond-like carbon (DLC) inclusive layer 8.

[0036] In an exemplary embodiment, the low-E coating system includes,from substrate 1 outwardly, titanium oxide (or dioxide) layer 2 about200 angstroms (Å) thick, silicon nitride (Si₃N₄) layer 3 about 100 Åthick, NiCrO_(x) layer 4 about 10 Å thick, silver (Ag) layer 5 about 85Å thick, NiCrO_(x) layer 6 about 10 Å thick, silicon nitride (Si₃N₄)layer 7 about 450 Å thick, and DLC inclusive layer(s) 8 as described inany embodiment of either of parent applications Ser. Nos. 09/303,548 or09/442,805. Optionally, each of layers 3 and 7 may include about 1-2%stainless steel in certain embodiments.

[0037] DLC inclusive layer 8 is preferably substantially non-polymerizedand substantially non-crystalline and makes up (either alone or incombination with another layer(s)) a protective DLC inclusive layer(s)or coating system 15 that is mechanically and chemically durable,scratch resistant, and protects the underlying portion (e.g., low-Earrangement of layers 2-7) of the low-E coating system. Thus, system 15provides durability enhancement (e.g., scratch resistance) to the low-Ecoating system, while not substantially adversely affecting the low-Echaracteristics of the low-E coating system. As will be furtherexplained below, protective coating system 15 may be a hydrophobiccoating system in certain embodiments of this invention when hydrophobicproperties are desired.

[0038] An advantage associated with certain embodiments of thisinvention is that DLC inclusive protective system 15 can be deposited orformed over low-E layer arrangement 2-7 via a low temperature depositionprocess (e.g., ion beam deposition as described below). For example,protective layer(s) system 15 can be deposited at temperatures nogreater than about 200 degrees C., more preferably no greater than about125 degrees C., even more preferably at temperatures no greater thanabout 75 degrees C., and most preferably at temperatures no greater thanabout 40 degrees C. (e.g., layer system 15 may be deposited atapproximate room temperature in certain embodiments). These lowtemperatures are compared to the 700-1,000 degree C. temperaturestypically required for depositing the non-amorphous polycrystallinediamond in the aforesaid '683 patent. As a result of the lowtemperatures used during the system 15 deposition process, theunderlying low-E layers 2-7 are not significantly damaged during thedeposition of protective layer system 15. Moreover, the amorphous DLC inlayer 8 provides excellent durability and scratch resistance, and may besubstantially transparent to visible light in certain embodiments.

[0039] In the FIG. 1 embodiment, DLC inclusive layer 8 may be made up ofor include any of the DLC inclusive layers described and/or illustratedin the parent commonly owned U.S. Ser. No. 09/303,548, filed May 3,1999, which is incorporated herein by reference, or the parent commonlyowned U.S. Ser. No. 09/442,805, filed Nov. 18, 1999, incorporated hereinby reference. Thus, DLC inclusive layer 8 preferably includes at leastsome amount of highly tetrahedral amorphous carbon (ta-C). Highlytetrahedral amorphous carbon (ta-C) forms sp³ carbon-carbon bonds, andis a special form of diamond-like carbon (DLC). In certain embodimentsof this invention, in DLC inclusive layer 8 at least about 40% (morepreferably at least about 60%, and most preferably at least about 80%)of the carbon-carbon bonds are of the sp³ carbon-carbon type. Theremainder of the bonds in layer 8 may be, for example, sp² carbon-carbonbonds, Si—C bonds, C—O bonds, or the like. The provision of at leastsome sp³ carbon-carbon bonds in layer 8 enables layer 8 to be morescratch resistant, hard, chemically resistant and substantiallytransparent. Layer 8, in certain embodiments, has a hardness of at leastabout 10 GPa, more preferably from about 25-80 GPa, due in large part tothe presence of the sp³ carbon-carbon bonds.

[0040] Substantially transparent dielectric layer 2 is optional, butwhen provided is preferably from about 100-500 Å thick, more preferablyfrom about 150-300 Å thick. Substantially transparent dielectric layer 3is preferably from about 20-200 Å thick, more preferably from about20-120 Å thick. First metal or metal oxide or metal nitride layer 4 ispreferably from about 7-50 Å thick, more preferably from about 7-30 Åthick. IR reflective layer 5 is preferably from about 50-250 Å thick,more preferably from about 100-200 Å thick. Second metal or metal oxideor metal nitride layer 6 is preferably from about 7-50 Å thick, morepreferably from about 7-20 Å thick. Substantially transparent dielectriclayer 7 is preferably from about 50-600 Å thick, more preferably fromabout 400-500 Å thick. Optionally, an additional metal oxide (e.g.,SnO₂, ZnO, In₂O₃) inclusive layer (not shown) may be provided over layer7 so as to be located between layers 7 and 8. In certain embodiments,DLC inclusive layer 8 may be from about 10 to 250 angstroms (Å) thick,or any other thickness discussed in any of the parent applications.

[0041] The layers 2-7 of the low-E arrangement may be made up of orinclude any of the low-E coating systems disclosed and/or described inany of U.S. Pat. Nos. 5,800,933 or 5,770,321, both of which are herebyincorporated herein by reference. Alternatively, any other suitablelow-E coating system may instead be used beneath the protective DLCinclusive layer system 15. Exemplary thicknesses of layers 2-7 areprovided in the '933 and/or '321 patents, as are exemplary materialswhich may be used for these layers.

[0042] Low-E performance characteristics of the low-E coating system ofthis invention are also provided in the '933 and/or '321 patents (thepresence of substantially transparent protective system 15 does notsubstantially adversely affect the low-E characteristics of theunderlying low-E portion of the system). For example, low-E coatingsystems herein preferably have a normal emissivity (E_(n)) of about 0.10or less (more preferably about 0.06 or less), a hemispherical emissivity(E_(h)) of about 0.11 or less (more preferably about 0.07 or less), asheet resistance (R_(s)) of about 10.0 ohms/square or less (morepreferably of about 5.0 ohms/square or less), and a visibletransmittance of at least about 70% (more preferably of at least about75%). Additionally, low-E coating systems herein preferably have asubstantially neutral visible reflectance color. Layers 2-7 may bedeposited, preferably by sputtering, via any of the techniques discussedin the '933 and/or '321 patents, or using any other suitable techniquein different embodiments of this invention.

[0043]FIG. 2(a) is a side cross sectional view of a coated articleincluding a low-E coating system according to an embodiment of thisinvention, wherein a diamond-like carbon (DLC) and fluoro-alkyl silane(FAS) inclusive protective coating system 15 including at least threelayers 9, 10 and 11 is provided on substrate 1 over the same low-Elayers 2-7 described above and illustrated in FIG. 1. Referring to theFIG. 2(a) embodiment, substrate 1 may be of glass, plastic, ceramic, orthe like. In certain embodiments, each of layers 9 and 10 of theprotective coating system 15 portion of the low-E system includes atleast some amount of highly tetrahedral amorphous carbon (ta-C). Asmentioned above, highly tetrahedral amorphous carbon (ta-C) forms sp³carbon-carbon bonds, and is a special form of diamond-like carbon (DLC).DLC inclusive layers 9 and 10 are preferably substantiallynon-crystalline and/or substantially non-polymerized in certainembodiments of this invention. FAS inclusive layer 11 is then appliedover layers 9, 10. Protective system 15 (to be deposited at the lowtemperatures described above) may function in a hydrophobic manner(i.e., it is characterized by high water contact angles θ and/or lowsurface energies as described below), and optionally may becharacterized by low tilt angle(s) β in certain embodiments. In general,the DLC inclusive layer(s) 9 and/or 10 provide durability, scratchresistance and/or hydrophobicity, while FAS inclusive layer 11 functionsto even further increase the contact angle θ of the protective coatingsystem 15 if desired.

[0044] In the FIG. 2 embodiment(s), DLC inclusive coating/layer system15 may comprise any of the DLC inclusive layer systems illustratedand/or described in one or both of parent applications Ser. Nos.09/583,862 and/or 09/303,548, both of which are incorporated herein byreference.

[0045] It is surmised that the surface of DLC inclusive layer 10includes highly reactive dangling bonds immediately after itsformation/deposition, and that the application of FAS inclusive layer 11onto the surface of layer 10 shortly after layer 10's formation enablestight binding and/or anchoring of FAS inclusive layer 11 to the surfaceof layer 10. This results in increased contact angle θ (improvedhydrophobicity) and a durable low-E coating system. In certainembodiments of this invention, it has been found that FAS inclusivelayer 11 bonds more completely to DLC inclusive layer 10 when FAS layer11 is applied on the upper surface of layer 10 within one hour afterlayer 10 is formed, more preferably within thirty minutes after layer 10is formed, and most preferably within twenty minutes after layer 10 isformed. Thus, a more durable coating system results when FAS inclusivelayer 11 is applied on DLC inclusive layer 10 shortly after layer 10 isformed.

[0046] Overlying layer 11 may be substantially all FAS, or onlypartially FAS in different embodiments of this invention. Layer 11preferably includes at least one compound having an FAS group. Generallyspeaking, FAS compounds generally comprise silicon atoms bonded to fourchemical groups. One or more of these groups contains fluorine andcarbon atoms, and the remaining group(s) attached to the silicon atomsare typically alkyl (hydrocarbon), alkoxy (hydrocarbon attached tooxygen), or halide (e.g., chlorine) group(s). Exemplary types of FAS foruse in layer 11 include CF₃(CH₂)₂Si(OCH₃)₃ [i.e., 3,3,3trifluoropropyl)trimethoxysilane]; CF₃(CF₂)₅(CH₂)₂Si(OCH₂CH₃)₃ [i.e.,tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane];CF₃(CH₂)₂SiCl₃; CF₃(CF₂)₅(CH₂)₂SiCl₃; CF₃(CF₂)₇(CH₂)₂Si(OCH₃)₃;CF₃(CF₂)₅(CH₂)₂Si(OCH₃)₃; CF₃(CF₂)₇(CH₂)₂SiCl₃; CF₃(CF₂)₇(CH₂)₂SiCH₃Cl₂;and/or CF₃(CF₂)₇(CH₂)₂SiCH₃(OCH₃)₂. These FAS material may be usedeither alone or in any suitable combination for layer 11. At leastpartial hydrolysate (hydrolysed) versions of any of these compounds mayalso be used. Moreover, it is noted that this list of exemplary FASmaterials is not intended to be limiting, as other FAS type materialsmay also be used in layer 11. While FAS inclusive layer 11 is appliedover layer 10 by physical rubbing (or buffing) in certain preferredembodiments of this invention, layer 11 could instead be applied in anyother suitable manner in other embodiments of this invention. It certainembodiments, FAS inclusive layer 11 may be thermally cured as describedbelow relative to FIG. 10.

[0047] Still referring to FIG. 2(a), according to certain embodiments ofthis invention, while DLC inclusive layers 9 and 10 each include DLC,the two layers are preferably deposited using different precursor orfeedstock gases so that the two layers have different characteristics(e.g., different hardnesses and/or densities). In an exemplaryembodiment, underlying or anchor DLC inclusive layer 9 is depositedusing an ion beam deposition technique utilizing a TMS(tetramethylsilane) inclusive precursor or feedstock gas; whileoverlying DLC inclusive layer 10 is deposited using an ion beamdeposition technique utilizing a C₂H₂ (acetylene) inclusive precursor orfeedstock gas. It is believed that the underlying layer 9 (e.g., asilicon or Si doped DLC alloy) deposited using TMS functions as abarrier layer to prevent certain impurities from getting into or out ofthe substrate. Moreover, when TMS is used in the deposition process ofunderlying anchor layer 9, the Si (silicon) in layer 9 helps to enableoverlying DLC inclusive layer 10 to better bond and/or adhere to low-Earrangement 2-7 via anchor layer 9.

[0048] Surprisingly, it has also been found that the use of anchor DLCinclusive layer 9 (e.g., deposited via TMS gas) provides a morecontinuous/contiguous coating on a substrate surface at very thinthicknesses as compared to a DLC inclusive layer deposited using C₂H₂(acetylene) gas directly on glass. As a result, anchor layer 9 (which isoptional herein, but preferred in certain embodiments) can be depositedfirst directly on layer 7 at a relatively thin thickness, and theoverlying layer 10 need not be as thick as would otherwise be required.In general, the thinner the layer 10, the higher the transmission of theoverall coating system. Moreover, the provision of anchor layer 9 mayenable improved yields to be achieved, as the occurrence of pinholes inthe protective coating system 15 is less likely.

[0049] Still referring to the FIG. 2(a) embodiment, in embodiments whereDLC inclusive layer 10 is formed on the substrate using a C₂H₂(acetylene) inclusive precursor or feedstock gas and underlying DLCinclusive layer 9 is formed on the substrate using at least a TMS(tetramethylsilane) inclusive precursor or feedstock gas, the layers 9and 10 tend to intermix with one another during the deposition process.Thus, there may not be a clear line delineating or separating the twolayers 9 and 10 in the final product due to this intermixing (i.e., ionmixing) of the material from the two layers. However, for purposes ofsimplicity, the two layers 9 and 10 are referred to and illustratedherein as separate layers due to the different deposition processes(e.g., gases and/or energies) used in their respective formations.

[0050] It has been found that the outer DLC inclusive layer 10 formedusing a hydrocarbon gas, such as C₂H₂ (acetylene), inclusive precursoror feedstock tends to have a greater hardness and density than doesunderlying DLC inclusive layer 9 formed using a TMS (tetramethylsilane)inclusive precursor or feedstock gas. For example, in certain exemplaryembodiments of this invention, overlying layer 10 may have an averagehardness (measured via a nano-indentation hardness measuring technique)of from about 45-85 GPa, more preferably from about 50-70 GPa, and mostpreferably from about 55-60 GPa. Meanwhile, underlying DLC inclusivelayer 9 may have an average hardness of from about 10-35 GPa, and morepreferably from about 15-30 GPa. Thus, the overlying layer 10 may beharder than the underlying layer 9 in certain embodiments, so as to makethe end product more scratch and/or abrasion resistant. Using anano-indentation hardness measuring technique, the final protectivecoating system 15, including layers 9-11, may have a hardness of atleast about 10 GPa, more preferably from about 25-60 GPa, and even morepreferably from about 30-45 GPa, which is at a hardness value betweenthe respective hardnesses of the two DLC inclusive layers 9 and 10.

[0051] Thus, protective coating system 15 includes silicon (Si) in DLCinclusive layer 9 which functions to improve the bonding characteristicsof overlying and harder DLC inclusive layer 10 to the underlying low-Esystem (e.g., via layer 7). For example, when layer 7 includes siliconnitride, the silicon (Si) in layer 9 enables excellent bonding of theDLC inclusive protective layer system 15 to the underlying low-Earrangement including layers 2-7. While the Si in layer 9 improves thebonding of layer 10 to the underlying substrate 1 (or layer 7), it ispreferred that less Si be provided in layer 10 than in layer 9 becausethe provision of Si in a DLC inclusive layer may result in decreasedscratch resistance and/or decreased hardness. Layer 10 may or may notinclude Si in different embodiments of this invention. While layer 9allows for improved bonding to the substrate and underlying low-Earrangement of layers 2-7, the provision of DLC and some sp³carbon-carbon bonds therein allows this anchor layer 9 to have ratherhigh hardness values so as to render the resulting product more durableand thus resistant to scratching, abrasions, chemicals, and the like.

[0052] In the FIG. 2(a) embodiment, anchor or intermediate DLC inclusivelayer 9 may be from about 10 to 250 angstroms (Å) thick, more preferablyfrom about 10 to 150 angstroms thick, and most preferably from about30-50 angstroms thick; while outer DLC inclusive layer 10 may be fromabout 10 to 250 angstroms thick, more preferably from about 10 to 150angstroms thick, and most preferably about 30-60 angstroms (Å) thick.FAS inclusive layer 11 may be from about 5-80 angstroms thick, morepreferably from about 20-50 angstroms thick. However, these thicknessesare not limiting and the layers may be of other appropriate thicknessesin certain embodiments of this invention.

[0053] In certain embodiments, layer 10 may have an approximatelyuniform distribution of sp³ carbon-carbon bonds throughout a largeportion of its thickness, so that much of the layer has approximatelythe same density. In such embodiments, layer 9 may include a lesserpercentage of sp³ carbon-carbon bonds near the interface with substrate1, with the percentage or ratio of sp³ carbon-carbon bonds increasingthroughout the thickness of the coating system 15 toward the outermostsurface of layer 10. In overlying DLC inclusive layer 10, at least about40% (more preferably at least about 60%, and most preferably at leastabout 80%) of the carbon-carbon bonds in the layer are of the sp³carbon-carbon type.

[0054] It is believed that the presence of sp³ carbon-carbon bonds inlayer 10 increases the density and hardness of the coating system,thereby enabling it to satisfactorily function in automotiveenvironments. Layer 10 may or may not include sp² carbon-carbon bonds indifferent embodiments, although formation of sp² carbon-carbon bonds islikely in both layers 9 and 10.

[0055] Protective DLC inclusive layer system 15 may be hydrophobic incertain embodiments of this invention, hydrophillic in other embodimentsof this invention, and/or neutral (neither hydrophobic nor hydrophillic)in other embodiments of this invention, depending upon the desiredapplication. When it is desired to provide a hydrophobic coating system,in order to improve the hydrophobic nature of coating system 15 atoms inaddition to carbon (C) may be provided in at least overlying layer 10 indifferent amounts in different embodiments. For example, in certainembodiments of this invention, layer 10 (taking the entire layerthickness, or only a thin 10 A thick layer portion thereof intoconsideration) may include in addition to the carbon atoms of the sp³carbon-carbon bonds, by atomic percentage, from about 0-20% Si (morepreferably from about 0-10%), from about 0-20% oxygen (O) (morepreferably from about 0-15%), and from about 5-60% hydrogen (H) (morepreferably from about 5-35% H). Optionally, layer 10 may include fromabout 0-10% (atomic percentage) fluorine (F) (more preferably from about0-5% F) in order to further enhance hydrophobic characteristics of thecoating (especially in the FIGS. 2(b) and 3 embodiments). In general,the provision of H in layer 10 reduces the number of polar bonds at thecoating's surface, thereby improving the coating system's hydrophobicproperties.

[0056] In certain embodiments, the outermost layer portion (e.g., 5-15angstrom thick outermost or exterior layer portion) of layer 10 mayinclude additional H and/or F atoms for the purpose of increasing thecoating system's hydrophobic qualities (especially in the FIGS. 2(b) and3 embodiments). In such embodiments, the deposition of additional Hatoms near layer 10's surface results in a more passive ornon-polar-coating proximate the surface thereof.

[0057] Two exemplary protective DLC inclusive hydrophobic coatingsystems 15 on a glass substrate (absent layers 2-7) were made and testedaccording to the FIG. 2(a) embodiment of this invention, as follows.

[0058] For the first coated article (sample #1), DLC inclusive layers 9and 10 were deposited on a soda-lime-silica glass substrate 1 using alinear ion beam deposition source (see FIGS. 5-6) in the followingmanner. TMS feedstock gas (50 sccm) was used at 1,500 Volts to depositlayer 9, while C₂H₂ feedstock gas (100 sccm) was used at 3,000 Volts todeposit layer 10 directly on top of layer 9. The underlying substratewas maintained at about 70 to 80 degrees F. during the depositionprocess. The scan speed for each of these was 36-50 in./minute. Each oflayers 9 and 10 was less than 50 angstroms thick (likely from about20-50 angstroms thick). Sample #2 was made in the same manner as sample#1, except that 750 Volts were used in depositing layer 9 (the same3,000 Volts were used for layer 10). Chart 1 below lists the measuredcharacteristics of the substrates 1 coated with layers 9 and 10, priorto deposition of FAS layer 11, for sample #s 1 and 2 of the FIG. 2(a)embodiment (absent layers 2-7). CHART 1 Initial Contact Angle θ Angle θ@ 25 Taber Cycles @ 300 @ 1,000 #1 95° 104° 103° 97° #2 95° 104° N/A 96°

[0059] As can be seen in Chart 1 above, each of these coated articles(substrate with DLC inclusive layers 9 and 10 thereon, but no FAS layer)had an initial contact angle θ of about 95 degrees. After beingsubjected to 25 cycles of a Taber abrasion test, each had a contactangle of about 104 degrees, and after being subject to 1,000 cycles ofthe Taber abrasion test the articles had contact angles of 97 and 96degrees, respectively.

[0060] An FAS layer 11 was then deposited on top of a layer 10 as shownin the FIG. 2(a) embodiment of this invention. Layer 11 was applied byphysically rubbing it onto the exterior surface of layer 10. Themeasurements from this coated article (i.e., sample #3 including each oflayers 9, 10 and 11 on soda-lime-silica glass substrate 1) are set forthbelow in Chart 2. CHART 2 Initial Contact Angle θ Angle θ @ 25 TaberCycles @ 300 @ 1,000 #3 109° 106° 100° 95°

[0061] As can be seen by comparing the results in Chart 2 (with optionalFAS layer 11) to the results of Chart 1 (without FAS layer 11), theprovision of FAS layer 11 improved at least the initial contact angle ofthe resulting coated article. Charts 1 and 2 show that the addition ofFAS layer 11 resulted in the initial contact angle improving from about95 degrees to about 109 degrees. Thus, hydrophobic properties of thearticle were improved with the addition of FAS inclusive layer 11.

[0062] In certain embodiments of this invention (in both FAS and non-FASembodiments), after 300 taber cycles the contact angle is preferably atleast about 90 degrees, more preferably at least about 95 degrees. In asimilar manner, after 1,000 tabler cycles the contact angle ispreferably at least about 80 degrees, more preferably at least about 90degrees.

[0063]FIG. 2(b) illustrates another embodiment of this invention, whichis the same as the FIG. 2(a) embodiment except that FAS inclusive layer11 is not provided. Thus, FAS inclusive layer 11 is clearly optional. Inthis FIG. 2(b) embodiment, the provision of DLC inclusive layers 9 and10 to make up DLC inclusive protective layer system 15 enables theunderlying low-E arrangement of layers 2-7 to be protected againstscratching, abrasions, etc. Still further, the protective layer system15 according to this embodiment may or may not be hydrophobic indifferent embodiments of this invention.

[0064]FIG. 3 illustrates yet another embodiment of this invention whichis the same as the FIG. 2(b) embodiment, except that an index matchinglayer 14 is provided between layer 2 and substrate 1. The purpose ofindex matching layer 14 is to reduce reflections off of the coatedarticle by approximately matching the respective indices of refractionof substrate 1 and layer 2. In an exemplary embodiment of thisinvention, index matching layer 14 may be of or include siliconoxynitride (SiO_(x)N_(y)), silicon oxide, silicon nitride, or anymixture thereof. Layer 14 may be deposited to a thickness of from about50 to 1,000 Å (more preferably from about 100 to 500 Å) in certainembodiments, preferably via sputtering.

[0065] In variations of the embodiments of FIGS. 2(a), 2(b) and 3described above, DLC inclusive layer 9 need not be included (i.e., layer9 is optional in each of the aforesaid embodiments). Thus, in any ofthese embodiments, a single DLC inclusive layer 10 may be provided underoptional FAS inclusive layer 11. In still further embodiments, one ormore intermediate layer(s) (e.g., of metal oxide) (not shown) may beprovided between layer 10 and low-E layering arrangement 2-7.

[0066] Referring to the different embodiments of FIGS. 1-3, DLCinclusive protective coating system 15 is at least about 75% transparentto or transmissive of visible light rays, preferably at least about 85%,and most preferably at least about 95%. In certain embodiments, theentire coated article of any of the FIGS. 1-3 embodiments may be atleast about 75% transmissive to visible light.

[0067] When substrate 1 is of glass, it may be from about 1.0 to 5.0 mmthick, preferably from about 2.3 to 4.8 mm thick, and most preferablyfrom about 3.7 to 4.8 mm thick. In certain embodiments, anotheradvantage of protective coating system 15 is that the ta-C (e.g., inlayers 9 and/or 10) therein may reduce the amount of soda (e.g., from asoda-lime-silica glass substrate 1) that can reach the surface of thecoated article and cause stains/corrosion. In such embodiments,substrate 1 may be soda-lime-silica glass and include, on a weightbasis, from about 60-80% SiO₂, from about 10-20% Na₂O, from about 0-16%CaO, from about 0-10% K₂O, from about 0-10% MgO, and from about 0-5%Al₂O₃. Iron and/or other additives may also be provided in the glasscomposition of the substrate 1. In certain other embodiments, substrate1 may be soda lime silica glass including, on a weight basis, from about66-75% SiO₂, from about 10-20% Na₂O, from about 5-15% CaO, from about0-5% MgO, from about 0-5% Al₂O₃, and from about 0-5% K₂O. Mostpreferably, substrate 1 is soda lime silica glass including, by weight,from about 70-74% SiO₂, from about 12-16% Na₂O, from about 7-12% CaO,from about 3.5 to 4.5% MgO, from about 0 to 2.0% Al₂O₃, from about 0-5%K₂O, and from about 0.08 to 0.15% iron oxide. Soda lime silica glassaccording to any of the above embodiments may have a density of fromabout 150 to 160 pounds per cubic foot (preferably about 156), anaverage short term bending strength of from about 6,500 to 7,500 psi(preferably about 7,000 psi), a specific heat (0-100 degrees C.) ofabout 0.20 Btu/1 bF, a softening point of from about 1330 to 1345degrees F., a thermal conductivity of from about 0.52 to 0.57 Btu/hrftF,and a coefficient of linear expansion (room temperature to 350 degreesC.) of from about 4.7 to 5.0×10⁻⁶ degrees F. Also, soda lime silicafloat glass available from Guardian Industries Corp., Auburn Hills,Mich., may be used as substrate 1. Any such aforesaid glass substrate 1may be, for example, green, blue or grey in color when appropriatecolorant(s) are provided in the glass in certain embodiments.

[0068] In certain other embodiments of this invention, substrate 1 maybe of borosilicate glass, or of substantially transparent plastic, oralternatively of ceramic. In certain borosilicate embodiments, thesubstrate 1 may include from about 75-85% SiO₂, from about 0-5% Na₂O,from about 0 to 4% Al₂O₃, from about 0-5% K₂O, from about 8-15% B₂O₃,and from about 0-5% Li₂O.

[0069] In still further embodiments, an automotive window (e.g.windshield or side window) including any of the above glass substrateslaminated to a plastic substrate may combine to make up substrate 1,with the low-E coating system(s) [see layers 2-15] of any of the FIGS.1-3 embodiments provided on the outside surface of such a window. Inother embodiments, substrate 1 may include first and second glass sheetsof any of the above mentioned glass materials laminated to one another,for use in window (e.g. automotive windshield, residential window,commercial architectural window, automotive side window, vacuum IGwindow, automotive backlight or back window, etc.) and other similarenvironments.

[0070] The low-E coating system (layers 2-15) of any of the embodimentsof FIGS. 1-3 may be provided on any surface of the substrate in suchapplications. For example, in vehicle applications (rear vehicle windowadjacent a vehicle back seat; front seat vehicle window; vehiclebacklite; vehicle windshield; etc.), the low-E coating system [layers2-15 of any of the FIGS. 1-3 embodiments] may be provided on theexterior surface of the substrate 1 so as to be exposed to theenvironmental elements surrounding the vehicle; or alternatively may beprovided on the interior surface of the substrate so as to be adjacentthe interior of the vehicle. Depending upon which surface of thesubstrate the low-E coating is located, any of a hydrophobic,hydrophillic or neutral protective DLC inclusive system 15 may beprovided as desired.

[0071] In hydrophobic embodiments where the DLC in protective system 15is provided in a hydrophobic manner, it is noted that hydrophobicperformance of the system of any of the FIGS. 1-3 embodiments is afunction of contact angle θ, surface energy γ, tilt angle β, and/orwettability or adhesion energy W.

[0072] The surface energy γ of a coating system may be calculated bymeasuring its contact angle θ (contact angle θ is illustrated in FIGS.4(a) and 4(b)). FIG. 4(a) shows the contact angle of a drop on asubstrate absent a hydrophobic embodiment of this invention, while FIG.4(b) shows the contact angle of a drop on a substrate having a coatingsystem thereon according to a hydrophobic embodiment of this invention(in FIG. 4(b) layers 2-7 are not shown for purposes of simplicity). Asessile drop 31 of a liquid such as water is placed on the coating asshown in FIG. 4(b). A contact angle θ between the drop 31 and underlyingcoating system (e.g., see layers 2-15 of any of the FIGS. 1-3embodiments, with the DLC and/or FAS inclusive layers on the outsidesurface) appears, defining an angle depending upon the interface tensionbetween the three phases in the point of contact. Generally, the surfaceenergy γ_(C) of a coating system can be determined by the addition of apolar and a dispersive component, as follows: γ_(C)=γ_(CP)+γ_(CD), whereγ_(CP) is the coating's polar component and γ_(CD) the coating'sdispersive component. The polar component of the surface energyrepresents the interactions of the surface which is mainly based ondipoles, while the dispersive component represents, for example, van derWaals forces, based upon electronic interactions. Generally speaking,the lower the surface energy γ_(C) of coating system 15, the morehydrophobic the coating and the higher the contact angle θ.

[0073] Adhesion energy (or wettability) W can be understood as aninteraction between polar with polar, and dispersive with dispersiveforces, between the coating system and a liquid thereon such as water.γ^(P) is the product of the polar aspects of liquid tension andcoating/substrate tension; while γ^(D) is the product of the dispersiveforces of liquid tension and coating/substrate tension. In other words,γ^(P)=γ_(LP)*γ_(CP); and γ^(D)=γ_(LD)*γ_(CD); where γ_(LP) is the polaraspect of the liquid (e.g. water), γ_(CP) is the polar aspect of coatingsystem; γ_(LD) is the dispersive aspect of liquid (e.g. water), andγ_(CD) is the dispersive aspect of the coating system. It is noted thatadhesion energy (or effective interactive energy) W, using the extendedFowkes equation, may be determined by:

[0074] W=[γ_(LP)*γ_(CP)]^(½)+[γ_(LD)*γ_(CD)]^(½)=γ₁(1+cosθ), where γ₁ isliquid tension and θ is the contact angle. W of two materials is ameasure of wettability indicative of how hydrophobic the coating systemis.

[0075] When analyzing the degree of hydrophobicity of outermostlayer/portion of the coating system (e.g., at layer(s) 8, 10, or 11)with regard to water, it is noted that for water γ_(LP) is 51 mN/m andγ_(LD) is 22 mN/m. In certain embodiments of this invention, the polaraspect γ_(CP) of surface energy of layers 8, 10 and 11 is from about 0to 0.2 (more preferably variable or tunable between 0 and 0.1) and thedispersive aspect γ_(CD) of the surface energy of layers 8, 10 and 11 isfrom about 16-22 mN/m (more preferably from about 16-20 mN/m). Using theabove-listed numbers, according to certain embodiments of thisinvention, the surface energy γ_(C) of layer 8, 10 and/or 11 (and thusthe corresponding coating system) is less than or equal to about 20.2mN/m, more preferably less than or equal to about 19.5 mN/m, and mostpreferably less than or equal to about 18.0 mN/m; and the adhesionenergy W between water and the coating system is less than about 25mN/m, more preferably less than about 23 mN/m, even more preferably lessthan about 20 mN/m, and most preferably less than about 19 mN/m. Theselow values of adhesion energy W and the coating system's surface energyγ_(C), and the high initial contact angles θ achievable, illustrate theimproved hydrophobic nature of the coating systems according todifferent embodiments of this invention. While layers 8, 10 and/or 11may (or may not) function to provide much of the hydrophobic nature ofthe protective coating system 15, optional underlying DLC inclusivelayer 9 in certain embodiments improves the bonding characteristics ofthe system 15 to the substrate 1 (e.g., glass substrate) and layers 2-7,and yet still provides adequate hardness characteristics regarding thecoating system as a whole.

[0076] The initial contact angle θ of a conventional glass substrate 1with sessile water drop 31 thereon is typically from about 22-24degrees, although it may dip as low as 17 or so degrees in somecircumstances, as illustrated in FIG. 4(a). Thus, conventional glasssubstrates are not particularly hydrophobic in nature. Whenhydrophobicity is desired, protective system 15 may be deposited in amanner so as to achieve a hydrophobic result in any of the mannersdiscussed in the parent application. In such hydrophobic embodiments,the provision of system 15 on substrate 1 causes the contact angle θ toincrease to the angles discussed herein, as shown in FIG. 4(b) forexample, thereby improving the hydrophobic nature of the article. Asdiscussed in Table 1 of Ser. No. 09/303,548, the contact angle θ of ata-C DLC layer is typically less than 50 degrees. However, the makeup ofcertain hydrophobic DLC-inclusive protective coating systems 15described herein enables the initial contact angle θ of the systemrelative to a water drop (i.e. sessile drop 31 of water) to be increasedin certain embodiments to at least about 55 degrees, more preferably toat least about 80 degrees, still more preferably to at least about 100degrees, even more preferably at least about 110 degrees, and mostpreferably at least about 125 degrees, thereby improving the hydrophobiccharacteristics of the DLC-inclusive coating system. An “initial”contact angle θ means prior to exposure to environmental conditions suchas sun, rain, abrasions, humidity, etc.

[0077] In certain preferred embodiments of this invention, layers 2-7are deposited on substrate 1 via a sputtering process (e.g., see thesputtering techniques discussed in the '321 and/or '933 patents,incorporated herein by reference). However, the layer(s) of protectiveDLC inclusive system 15 are preferably deposited over layers 2-7 via anion beam deposition technique. Thus, different deposition techniques arepreferably used to deposit layers 2-15 on substrate 1. However, it isnoted that these deposition techniques are for purposes of example onlyand are not intended to be limiting; any suitable depositiontechnique(s) may be used in different embodiments of this invention.

[0078] FIGS. 5-6 illustrate an exemplary linear or direct ion beamsource 25 which may be used to deposit layers 8, 9 and 10 of protectivecoating system 15, clean a substrate, or surface plasma treat a DLCinclusive coating system 15 with H and/or F according to differentembodiments of this invention. Ion beam source 25 includes gas/powerinlet 26, anode 27, grounded cathode magnet portion 28, magnet poles 29,and insulators 30. A 3 kV DC power supply may be used for source 25 insome embodiments. Linear source ion deposition allows for substantiallyuniform deposition of layers 9 and 10 as to thickness and stoichiometry.As mentioned above, FAS inclusive layer 11 is preferably not appliedusing ion beam technology (rubbing/buffing is a preferred depositiontechnique for layer 11) nor are layers 2-7, although they may be formedin such a manner in certain embodiments of this invention.

[0079] Ion beam source 25 is based upon a known gridless ion sourcedesign. The linear source is composed of a linear shell (which is thecathode and grounded) inside of which lies a concentric anode (which isat a positive potential). This geometry of cathode-anode and magneticfield 33 gives rise to a close drift condition. The magnetic fieldconfiguration further gives rise to an anode layer that allows thelinear ion beam source to work absent any electron emitter. The anodelayer ion source can also work in a reactive mode (e.g. with oxygen andnitrogen). The source includes a metal housing with a slit in a shape ofa race track as shown in FIGS. 5-6. The hollow housing is at aroundpotential. The anode electrode is situated within the cathode body(though electrically insulated) and is positioned just below the slit.The anode can be connected to a positive potential as high was 3,000 ormore volts (V). Both electrodes may be water cooled in certainembodiments. Feedstock/precursor gases, described herein, are fedthrough the cavity between the anode and cathode. The gas(es) useddetermines the make-up of the resulting layer(s) deposited on anadjacent substrate 1. Herein, a layer is deemed deposited “on” thesubstrate regardless of whether other layer(s) are located between thatlayer and the substrate. In other words, the term “on” herein coversboth directly on and indirectly on with other layer(s) therebetween(e.g., layer system 15 is “on” substrate 1 in the FIGS. 1-3 embodimentseven though other layers are provided therebetween).

[0080] The linear ion source also contains a labyrinth system thatdistributes the precursor gas (e.g., TMS (i.e., (CH₃)₄Si ortetramethylsilane); acetylene (i.e., C₂H₂); 3MS (i.e.,trimethyldisilane); DMS (i.e., dichloro-dimethylsilane); hexane;methane; HMDSO (i.e., hexamethyldisiloxane); TEOS (i.e.,tetraethoxysilane), etc.) fairly evenly along its length and whichallows it to supersonically expand between the anode-cathode spaceinternally. The electrical energy then cracks the gas to produce aplasma within the source. The ions are expelled out at energies in theorder of eVc-a/2 when the voltage is Vc-a. The ion beam emanating fromthe slit is approximately uniform in the longitudinal direction and hasa Gaussian profile in the transverse direction. Exemplary ions 34 areshown in FIG. 6. A source as long as one meter may be made, althoughsources of different lengths are anticipated in different embodiments ofthis invention. Finally, electron layer 35 is shown in FIG. 6 completesthe circuit thereby enabling the ion beam source to function properly.

[0081] An advantageous of the ion beam source of FIGS. 5-6 is that itcan be used to deposit protective coating system 15 at temperaturese.g., from room temperature up to about 200 degrees C. In other words,it can be used to deposit system 15 over top of low-E layers 2-7 attemperatures which are low enough so that layers 2-7 are notsignificantly damaged during the deposition of DLC inclusive protectivecoating system 15.

[0082] In alternative embodiments of this invention, an ion beam sourcedevice or apparatus as described and shown in FIGS. 1-3 of U.S. Pat. No.6,002,208 (hereby incorporated herein by reference in its entirety) maybe used to deposit/form DLC inclusive layers 9, 10 on substrate 1 inaccordance with either the FIG. 1, FIG. 2, or FIG. 3 embodiment of thisinvention. One or multiple such ion beam source devices may be used.

[0083] In certain embodiments, the same ion beam source 25 may be usedto deposit both of layers 9 and 10; one after the other. In otherembodiments of this invention two separate ion beam sources may beprovided, a first for depositing layer 9 on substrate 1 over layers 2-7and the second for depositing layer 10 over layer 9. After layers 9 and10 are deposited, FAS inclusive layer 11 is preferably applied thereonvia a rubbing process of any other suitable deposition technique.

[0084] Referring to FIG. 7, tilt angle β characteristics associated withcertain embodiments of this invention will be explained. In ahydrophobic coating, it is often desirable in certain embodiments tohave a high contact angle θ (see FIG. 4(b)) in combination with a lowtilt angle β. As shown in FIG. 7, tilt angle β is the angle relative tothe horizontal 43 that the coated article must be tilted before a 30 μL(volume) drop 41 (e.g., of water) thereon begins to flow down the slantat room temperature without significant trail. A low tilt angle meansthat water and/or other liquids may be easily removed from the coatedarticle upon tilting the same or even in high wind conditions. Incertain embodiments of this invention, coated articles herein have aninitial tilt angle β of no greater than about 30 degrees, morepreferably no greater than about 20 degrees, and even more preferably nogreater than about 10 degrees. In certain embodiments, the tilt angledoes not significantly increase over time upon exposure to theenvironment and the like, while in other embodiments it may increase tosome degree over time.

[0085] Referring to FIGS. 2(a) and 5-6, an exemplary method ofdepositing a low-E coating system on substrate 1 will now be described.This method is for purposes of example only, and is not intended to belimiting.

[0086] Initially, low-E layers 2-7 are sputtered onto substrate 1 usingappropriate targets as described in any of U.S. Pat. Nos. 5,770,321 or5,800,933, both incorporated herein by reference. After sputterdeposition of layers 2-7, the deposition process for DLC inclusivelayers 9 and 10 begins using a linear ion beam deposition technique viaone or two ion beam source(s) as shown in FIGS. 5-6, or in FIGS. 1-3 ofthe '208 patent; with a conveyor having moved the substrate 1 withlayers 2-7 thereon to a position under the ion beam source. The ion beamsource functions to deposit a DLC inclusive layer 9 on substrate 1 overlayers 2-7 so as to be in contact with layer 7 (e.g., layer 7 may be ofsilicon nitride to improve bonding between layers 7 and 9), with atleast TMS being used as the precursor or feedstock gas fed through thesource for the deposition of layer 9. Because of the Si in the TMS gasused in the source, the resulting layer 9 formed on substrate includesat least Si as well as DLC. The Si portion of DLC inclusive layer 9enables good bonding of layer 9 to layer 7, and thus will also improvethe bonding characteristics of layer 10 to the substrate 1.

[0087] After layer 9 has been formed, either the same or another ionbeam source is used to deposit layer 10 over (directly on in preferredembodiments) layer 9. To deposit overlying DLC inclusive layer 10,another gas such as at least C₂H₂ is fed through the source so that thesource expels the ions necessary to form layer 10 overlying layer 9 onsubstrate 1 and over layers 2-7. The C₂H₂ gas may be used alone, or inexemplary alternative embodiments the gas may be produced by bubbling acarrier gas (e.g. C₂H₂) through a precursor monomer (e.g. TMS or 3MS)held at about 70 degrees C. (well below the flashing point). Acetylenefeedstock gas (C₂H₂) is used in certain embodiments for depositing layer10 to prevent or minimize/reduce polymerization (layer 9 may bepolymerized in certain embodiments) and to obtain an appropriate energyto allow the ions to penetrate the surface of layer 9 and subimplanttherein, thereby causing layer 10 to intermix with layer 9 in at leastan interface portion between the layers. The actual gas flow may becontrolled by a mass flow controller (MFC) which may be heated to about70 degrees C. In certain optional embodiments, oxygen (O₂) gas may beindependently flowed through an MFC. The temperature of substrate 1 maybe room temperature; an arc power of about 1000 W may be used; precursorgas flow may be about 25 sccm; the base pressure may be about 10⁻⁶ Torr.The optimal ion energy window for the majority of layers 9, 10 is fromabout 100-1,000 eV (preferably from about 100-400 eV) per carbon ion. Atthese energies, the carbon in the resulting layers 9 and/or 10 emulatesdiamond, and sp³ C—C bonds form. However, compressive stresses candevelop in ta-C when being deposited at 100-150 eV. Such stress canreach as high as 10 GPa and can potentially cause delamination from manysubstrates. It has been found that these stresses can be controlled anddecreased by using an ion energy during the deposition process in arange of from about 200-1,000 eV.

[0088] As stated above, layers 9 and 10 intermix with one another at theinterface between the two layers, thereby improving the bonding betweenthe layers. At particle energies (carbon energies) of several hundredeV, a considerable material-transport can take place over several atomicdistances. This is caused by the penetration of fast ions and neutralsas well as by the recoil displacement of struck atoms. At sufficientlyhigh particle energies and impact rates, there is an enhanced diffusionof the thermally agitated atoms near the film surface that occurs viathe continuously produced vacancies. In the formation of ta-C:H, theseeffects can help improve film adhesion by broadening the interface(i.e., making it thicker, or making an interfacial layer between the twolayers 9 and 10 due to atom mixing). Layers 9 and 10 are contiguous dueto this intermixing, and this “smearing” between the layers enhances theadhesion of layer 10 to both layer 9 and thus the substrate 1.

[0089] High stress is undesirable in the thin interfacing portion oflayer 9 that directly contacts the surface of layer 7 in the FIG. 2(a)embodiment. Thus, for example, the first 1-40% thickness (preferably thefirst 1-20% and most preferably the first 5-10% thickness) of layer 9may optionally be deposited using high anti-stress energy levels of fromabout 200-1,000 eV, preferably from about 400-500 eV. Then, after thisinitial interfacing layer portion of layer 9 has been grown, the ionenergy in the ion deposition process may be decreased (either quickly orgradually while deposition continues) to about 100-200 eV, preferablyfrom about 100-150 eV, to grow the remainder of layer(s) 9 and/or layer10. Thus, in certain embodiments, because of the adjustment in ionenergy and/or gases during the deposition process, DLC inclusive layers9, 10 may optionally have different densities and different percentagesof sp³ C—C bonds at different layer portions thereof (the lower the ionenergy, the more sp³ C—C bonds and the higher the density).Alternatively, the same energy may be used to deposit all of layers 9and/or 10 in certain embodiments of this invention.

[0090] While direct ion beam deposition techniques are preferred incertain embodiments, other methods of deposition may also be used indifferent embodiments. For example, filtered cathodic vacuum arc ionbeam techniques may be used to deposit layers 9, 10. Also, in certainembodiments, CH₄ may be used as a feedstock gas during the depositionprocess instead of or in combination with the aforesaid C₂H₂ gas.

[0091] Optionally, the outer surface of layer 10 may be treated using aplasma treatment by another source or grafting procedure (prior toformation of FAS layer 11). This technique using an ion beam source mayremove certain polar functional groups at the outermost surface of layer10, thereby altering the surface chemical reactivity (i.e. loweringsurface energy) of layer 10. In such optional embodiments, after aconveyor has moved the DLC-coated substrate from the source station to aposition under this another source, the plasma treatment by this sourcemay introduce, e.g., hydrogen (H) atoms into the outermost surface oflayer 10, thereby making layer 10's surface substantially non-polar andless dense than the rest of layer 10. These H atoms are introduced,because H₂ and/or ArH₂ feedstock gas is used by this source in certainembodiments. Thus, this source does not deposit any significant amountsof C atoms or Si atoms; but instead treats the outermost surface oflayer 10 by adding H atoms thereto in order to improve its hydrophobiccharacteristics. This plasma treatment may also function to roughen theotherwise smooth surface. It is noted that H₂ feedstock gas is preferredin the ion beam source when it is not desired to roughen the surface ofprotective coating system 15, while ArH₂ feedstock gas is preferred insurface roughing embodiments. In other optional embodiments, this sourcemay be used to implant F ions/atoms in to the outermost surface of layer10.

[0092] After DLC inclusive layers 9 and 10 have been formed on substrate1 and over layers 2-7, FAS inclusive layer 11 is applied thereto (e.g.,by rubbing or otherwise applying this layer 11 in any other suitablemanner).

[0093] Optionally, after FAS inclusive layer 11 has been formed on thesubstrate 1, the coated article may be heated (e.g., up to about 100degrees C. in certain embodiments, or up to about 300 degrees C. inother embodiments). Surprisingly, it has been found that heating thecoated article in such a manner improves the durability of FAS inclusivelayer 11, and thus of the overall coating system. It is thought thatsuch hearing may “cure” layer 11 or otherwise cause it to morecompletely bond to itself and/or layer 10.

[0094] In this regard, FIG. 10 is a flowchart illustrating certain stepstaken in the manufacture of a coated article according to an embodimentof this invention. A substrate (e.g., glass, plastic, or ceramicsubstrate) is provided at step 24, with layers 2-7 thereon. At least oneDLC inclusive protective layer (e.g., one or more of layers 8, 9, 10) isdeposited on the substrate at step 25. Following formation of the DLCinclusive layer(s), an FAS compound inclusive layer (e.g., layer 11) isdeposited on the substrate in step 26. The FAS inclusive layer ispreferably deposited directly on the upper surface of a DLC inclusivelayer in certain embodiments of this invention, but alternatively otherlayer(s) may be located between the DLC inclusive layer(s) and the FASinclusive layer.

[0095] After the DLC and FAS inclusive layers have been deposited on thesubstrate, the entire coated article (or alternatively only the FASinclusive layer) is subjected to heating for curing purposes in step 27.The heating may take place in any suitable oven or furnace, oralternatively may be implemented by an IR or any other type of localizedheating device. This heating may be at a temperature of from about 50 to300 degrees C., more preferably at a temperature of from about 70 to 200degrees C., and even more preferably at a temperature of from about70-100 degrees C. However, it is noted that as the heating time goes up,the required temperature goes down. Thus, for purposes of example only,the heating may be conducted at about 80 degrees C. for about 60 minutes(1 hour). Alternatively, the heating may be conducted at about 250degrees C. for about 5 minutes, or at about 150 degrees C. for about 20minutes. The time which the coated article is subjected to heating mayrange from about 20 seconds to 2 hours in certain embodiments of thisinvention, more preferably from about one (1) minute to one (1) hour,depending on the temperature used. In preferred embodiments of thisinvention, at least the FAS inclusive layer (and preferably the entirecoated article) is heated at a temperature and for a period of timesufficient to achieve one or more of the advantages discussed above.Thus, when it is desired to keep the temperature(s) of layers 1-7 as lowas possible, layer 11 need not be heated at all; or alternatively it maybe heated at lesser temperature(s), e.g., 75 degrees C., or 40 degreesC., for longer periods of time than would be required at highertemperatures.

[0096] DLC inclusive protective coating system 15 according to differentembodiments of this invention may have the following characteristics:coefficient of friction of from about 0.02 to 0.15; good abrasionresistance; an average density of from about 2.0 to 3.0 g/cm²;permeability barrier to gases and ions; surface roughness less thanabout 0.5 nm; inert reactivity to acids, alkalis, solvents, salts andwater; corrosion resistance; variable or tunable surface tension;tunable optical bandgap of from about 2.0 to 3.7 eV; IR transmission @10 μm of at least about 85%; UV transmission @ 350 μnm of no greaterthan about 30%; tunable refractive index @ 550 nm [n=1.6 to 2.3;k=0.0001 to 0.1], permittivity @ GHz 4.5; an undoped electricalresistivity of at least about 10¹⁰ Ω/cm; dielectric constant of about 11@ 10 kHz and 4 @ 100 MHz; an electrical breakdown strength (V cm⁻¹) ofabout 10⁶; thermal coefficient of expansion of about 9×10⁻⁶/C; andthermal conductivity of about 0.1 Wcm K.

[0097] Three examples of optional TMS-formed DLC inclusive anchor layers9 are as follows. Each such layer 9 was deposited on a substrate usingtetramethylsilane (TMS) and O₂ gas introduced within the linear ion beamsource apparatus of FIGS. 5-6. All samples were of approximately thesame thickness of about 750 A. A low energy electron flood gun was usedto sharpen the spectral analysis conducted by x-ray photo electronspectroscopy (XPS) for chemical analysis. In XPS analysis of a layer 9,high energy x-ray photons (monochromatic) impinge on the surface of thelayer. Electrons from the surface are ejected and their energy andnumber (count) measured. With these measurements, one can deduce theelectron binding energy. From the binding energy, one can determinethree things: elemental fingerprinting, relative quantity of elements,and the chemical state of the elements (i.e. how they are bonding).Components used in the XPS analysis include the monochromatic x-raysource, an electron energy analyzer, and electron flood gun to preventsamples from charging up, and an ion source used to clean and depthprofile. Photoelectrons are collected from the entire XPS fieldsimultaneously, and using a combination of lenses before and after theenergy analyzer are energy filtered and brought to a channel plate. Theresult is parallel imaging in real time images. Sample Nos. 1-3 of DLCinclusive layer 9 were made and analyzed using XPS, which indicated thatthe samples included the following chemical elements by atomicpercentage (H was excluded from the chart below). CHART 3 Sample No. C OSi F 1 54.6% 23.7% 20.5% 1.2% 2 45.7% 21.7% 32.7% 0% 3 59.5% 22.7% 17.8%0%

[0098] H was excluded from the XPS analysis because of its difficulty tomeasure. Thus, H atoms present in the coating Sample Nos. 1-3 of Chart 3were not taken into consideration for these results. For example, ifSample No. 1 in Chart 3 included 9% H by atomic percentage, then theatomic percentages of each of the above-listed elements C, O, Si and Fwould be reduced by an amount so that all five atomic percentagestotaled 100%. As can be seen, F is optional and need not be provided.Oxygen is also optional.

[0099] While TMS is described above as a primary precursor or feedstockgas utilized in the ion beam deposition source for depositing theoptional underlying DLC inclusive layer 9, other gases may in additionor instead be used. For example, other gases such as the following maybe used either alone, or in combination with TMS, to form layer 9:silane compounds such as TMS, diethylsilane, TEOS,dichlorodimethylsilane, trimethyldisilane, hexamethyldisiloxane,organosilane compounds; organosilazane compounds such ashexamethyldisilazane and tetramethyldisilazane; and/or organo-oxysiliconcompounds such as tetramethyldisiloxane, ethoxytrimethylsilane, andorgano-oxysilicon compounds. Each of these gases includes Si; and eachof these gases may be used either alone to form layer 9, or incombination with one or more of the other listed gases. In certainembodiments, the precursor gas may also further include N, F and/or O inoptional embodiments, for layer 9 and/or layer 10.

[0100] With regard to layer 10, a hydrocarbon gas such as acetylene ispreferred for forming the layer. However, other gases such as ethane,methane, butane, cyclohexane, and/or mixtures thereof may also (orinstead) be used in the ion beam source to form layer 10.

[0101] In certain embodiments of this invention (e.g., see FIGS. 1-3),protective coating system 15 (and thus the entire low-E coating system)has a contact angle of at least about 70°, more preferably at leastabout 80°, and even more preferably at least about 100° after a taberabrasion resistance test has been performed pursuant to ANSI Z26.1. Thetest utilizes 1,000 rubbing cycles of a coating system, with a load aspecified in Z26.1 on the wheel(s). Another purpose of this abrasionresistance test is to determine whether the coated article is resistiveto abrasion (e.g. whether hazing is less than 4% afterwards). ANSI Z26.1is hereby incorporated into this application by reference.

[0102] FIGS. 8-9 illustrate the makeup of a protective coating system 15including layers 9, 10, and 11 deposited on a substrate (absent layers2-7) according to an embodiment of this invention. However, FIGS. 8 and9 must be looked at together to span the entire coating system of layers9-11. FIG. 8 shows the make-up with regard to C, O and Si for layers 9and 10, while FIG. 9 shows the make-up with regard to C, O and Si forlayer 11, throughout the respective thicknesses of these layers. X-rayPhotoelectron Spectroscopy (XPS)/Electron Spectroscopy for ChemicalAnalysis (ESCA) was used to develop these graphs from sample products.This is used to characterize inorganic and organic solid materials. Inorder to perform such measurements on sample products as was done withregard to FIGS. 8-9, surfaces of the coating system were excited with Almonochromatic x-rays (1486.6 eV) and the photoelectrons ejected from thesurface were energy analyzed. Low resolution analysis, i.e., a surveyscan, can be used to identify elements (note that H, He, and F were notincluded in the analysis of FIGS. 8-9 even though at least H and/or Fwere present in the coating system) and establish the illustratedconcentration table in units of atomic percentage (%). Detection limitswere from about 0.1 to 0.05 atom %. High resolution analysis ofindividual photoelectron signals, i.e., C 1s, can be used to identifychemical bonding and/or oxidation state. Information on the surface isobtained from a lateral dimension as large as 1 mm diameter and from adepth of 0-10 μm. To acquire information from slightly greater depths,angle resolved measurements can be made.

[0103]FIG. 8 illustrates the makeup with regard to C, O and Sithroughout the thicknesses of DLC inclusive layers 9 and 10 ofprotective coating system 15 of the FIG. 2(a) embodiment (i.e., no FASlayer was on layers 9 and 10 when this data was measured, so as toresemble FIG. 2(b)). Cycle number 1 is at the outer surface of layer 10,while cycle number 19 is believed to be within the underlying glasssubstrate 1 (remember, layers 9-10 were deposited directly on a glasssubstrate absent layers 2-7 for purposes of this test). Thus, it isbelieved that the interface between glass substrate 1 and underlying DLCinclusive layer 9 is at about cycle number 15 where the C % begins tosignificantly decrease. The “time” and “depth” columns refers to depthinto layers 10, 9 from the exterior surface of layer 10 as compared tothe depth into a conventional SiO₂ that would be achieved over the sametime period. Thus, the angstrom depth illustrated in FIG. 8 is not theactual depth into layers 10, 9, but instead is how deep into a SiO₂layer the sputtering would reach over the corresponding time. In FIG. 8,cycle number 1 may be affected from contamination of the outer surfaceof layer 10 and may be disregarded in effect. At least cycle numbers 2-6refer or correspond to DLC inclusive layer 10 as evidenced by the highcarbon amounts (i.e., greater than 94% C in layer 10 according to FIG.8). Meanwhile, at least cycle numbers 9-13 refer or correspond tounderlying DLC inclusive layer 9, as evidence by the lower C amountsshown in FIG. 8. Thus, it can be seen that layer 9 includes less C thanlayer 10, and is therefor less dense and less hard. Moreover, it can beseen that layer 9 includes more Si than layer 10 (and optionally moreoxygen (O)). Cycle numbers 7-8 refer or correspond to the interface orintermixing layer portion between layers 9 and 10; as the coating system15 at these thickness portions includes C and Si amounts between theamounts in respective layers 9 and 10. Thus, these cycle numbers 7-8illustrate the intermixing (i.e., subimplantation of atoms from layer 10in layer 9) or smearing between layers 9, 10 discussed herein.Meanwhile, cycle numbers 14-15 refer or correspond to the interfaciallayer between layer 9 and the glass substrate, while cycle numbers 16-19refer or correspond to the glass itself with its high SiO₂ content.

[0104]FIG. 9 illustrates a similar make-up, but of FAS layer 11 (i.e.,with regard to only C, O and Si throughout the thickness of layer 11).The layer 11 analyzed in FIGS. 9-10 was of the CF₃(CH₂)₂Si(OCH₃)₃ typeof FAS. Cycle number 1 is at the exterior surface of layer 11 wherelayer 11 meets the surrounding atmosphere, while cycle number 11 isbelieved to be in layer 11 near where the layer 11 meets the exteriorsurface of DLC inclusive layer 10. As can be seen by comparing FIGS. 8and 9, the FAS inclusive layer 11 has much less carbon than does layer10.

[0105]FIG. 11 is a graph illustrating “n” and “k” values for differentDLC inclusive layers according to certain embodiments of this invention.Curves 1 n and 1 k illustrate the “n” and “k” values for a DLC inclusivelayer formed using C₂H₂ gas, respectively. Curves 2 n and 2 k illustratethe “n” and “k” values for a DLC inclusive layer formed using TMS gas,respectively. Curves 3 n and 3 k illustrate the “n” and “k” values for aDLC inclusive layer formed using C₂H₂/HMDSO gas, respectively. As can beseen, the DLC inclusive layer formed using C₂H₂ gas generally has higher“n” and “k” values than the other two DLC inclusive layers. The indicesof refraction may be utilized so that a DLC inclusive layer adjacent alayer such as silicon nitride in certain embodiments of this inventiondoes not result in too much undesirable reflection(s). In other words,different DLC inclusive layers may be utilized in an attempt to closelymatch indices of refraction of DLC layer(s) with indices of layers suchas silicon nitride in order to reduce reflections off of the coatedarticle.

[0106] As will be appreciated by those skilled in the art, coatedarticles according to different embodiments of this invention may beutilized in the context of automotive windshields, automotive sidewindows, automotive backlites (i.e., rear windows), architecturalwindows, residential windows, ceramic tiles, shower doors, and the like.

[0107] Once given the above disclosure, many other features,modifications, and improvements will become apparent to the skilledartisan. Such other features, modifications, and improvements are,therefore, considered to be a part of this invention, the scope of whichis to be determined by the following claims.

What is claimed is:
 1. A coated article comprising: a substrate; a low-Ecoating system provided on said substrate, said low-E coating systemincluding at least one infrared (IR) reflecting layer and a protectivesubstantially non-crystalline diamond-like carbon (DLC) inclusive layerprovided in a position such that said IR reflecting layer is locatedbetween said substrate and said protective DLC inclusive layer.
 2. Thecoated article of claim 1, wherein said DLC inclusive layer includeshighly tetrahedral amorphous carbon, and wherein the coated article hasan initial contact angle θ of at least about 55 degrees.
 3. The coatedarticle of claim 2, wherein at least about 40% of carbon-carbon (C—C)bonds in said DLC inclusive layer are sp³ carbon-carbon bonds.
 4. Thecoated article of claim 1, wherein said DLC inclusive layer has anaverage density of at least about 2.4 gm/cm³.
 5. The coated article ofclaim 1, where said low-E coating system is provided in a manner so thatthe coated article has a normal emissivity of no greater than about0.10, a hemispherical emissivity of no greater than about 0.11, and asheet resistance of no greater than about 10.0 ohms/square.
 6. Thecoated article of claim 5, wherein said low-E coating system is providedin a manner so that the coated article has a normal emissivity of nogreater than about 0.06, a hemispherical emissivity of no greater thanabout 0.07, and a sheet resistance of no greater than about 5.0ohms/square, and wherein the coated article has an initial contact angleθ of at least about 80 degrees.
 7. The coated article of claim 5,wherein the coated article has a visible transmittance of at least about75%.
 8. The coated article of claim 1, wherein said DLC inclusive layeris deposited via an ion beam deposition process over the IR reflectinglayer in a manner such that the IR reflecting layer is maintained attemperature(s) no greater than about 200 degrees C. during the ion beamdeposition process for depositing the DLC inclusive layer.
 9. The coatedarticle of claim 1, wherein said low-E coating system further includes afirst dielectric layer disposed between said IR reflecting layer andsaid substrate, and a second dielectric layer disposed between said IRreflecting layer and said DLC inclusive layer.
 10. The coated article ofclaim 9, wherein said first dielectric layer comprises TiO₂ and saidsecond dielectric layer comprises silicon nitride.
 11. The coatedarticle of claim 1, wherein said low-E coating system comprises, fromsaid substrate outwardly, a layer system including: a) a layer oftransparent dielectric material; b) a dielectric layer of siliconnitride; c) a Ni inclusive layer; d) said IR reflecting layer includingAg; e) a Ni inclusive layer; f) a dielectric layer of silicon nitride;and g) said DLC inclusive layer.
 12. The coated article of claim 11,wherein said low-E coating system comprises first and second DLCinclusive layers located outwardly of said IR reflecting layer.
 13. Thecoated article of claim 12, wherein each of said first and second DLCinclusive layers includes highly tetrahedral amorphous carbon.
 14. Thecoated article of claim 1, further comprising a fluoro-alkyl silane(FAS) compound inclusive layer located on said substrate such that saidDLC inclusive layer is located between said FAS compound inclusive layerand said IR reflecting layer.
 15. The coated article of claim 1, whereinsaid low-E coating system has an initial contact angle θ of at leastabout 55 degrees, and said DLC inclusive layer has an average hardnessof at least about 10 GPa.
 16. The coated article of claim 1, whereinsaid low-E coating system includes first and second DLC inclusivelayers, said first DLC inclusive layer including silicon (Si) and beingprovided between said second DLC inclusive layer and said substrate; andwherein said second DLC inclusive layer is deposited in a manner so thatat least a portion of said second DLC inclusive layer has a greaterhardness and higher density than said first DLC inclusive layer.
 17. Thecoated article of claim 16, wherein said low-E coating system furtherincludes an FAS inclusive layer provided on said second DLC inclusivelayer, so that said second DLC inclusive layer is located between saidfirst DLC inclusive layer and said FAS inclusive layer.
 18. The coatedarticle of claim 1, wherein said coated article has an initial contactangle of at least about 80 degrees.
 19. The coated article of claim 18,wherein said initial contact angle is at least about 100 degrees. 20.The coated article of claim 1, wherein said low-E coating system has asurface energy γ_(C) of less than or equal to about 20.2 mN/m.
 21. Thecoated article of claim 20, wherein said low-E coating system has asurface energy γ_(C) of less than or equal to about 19.5 mN/m.
 22. Thecoated article of claim 1, further comprising a fluoro-alkyl silane(FAS) compound inclusive layer located on said substrate such that saidDLC inclusive layer is located between said FAS compound inclusive layerand said IR reflecting layer; and wherein said FAS compound includes atleast one of: CF₃(CH₂)₂Si(OCH₃)₃; CF₃(CF₂)₅(CH₂)₂Si(OCH₂CH₃)₃;CF₃(CH₂)₂SiCl₃; CF₃(CF₂)₅(CH₂)₂SiCl₃; CF₃(CF₂)₇(CH₂)₂Si(OCH₃)₃;CF₃(CF₂)₅(CH₂)₂Si(OCH₃)₃; CF₃(CF₂)₇(CH₂)₂SiCl₃; CF₃(CF₂)₇(CH₂)₂SiCH₃Cl₂;and CF₃(CF₂)₇(CH₂)₂SiCH₃(OCH₃)₂.
 23. The coated article of claim 16,wherein said first DLC inclusive layer comprises more silicon (Si) thansaid second DLC inclusive layer.
 24. The coated article of claim 23,wherein each of said first and second DLC inclusive layers include sp³carbon-carbon bonds.
 25. A coated article comprising: a substrate; atleast one dielectric layer on said substrate; an IR reflecting layer onsaid substrate, wherein said dielectric layer is located between said IRreflecting layer and said substrate; a hydrophobic coating systemincluding diamond-like carbon (DLC), wherein said IR reflecting layer islocated between said hydrophobic coating system and said substrate; andwherein said hydrophobic coating system has an initial contact angle θwith a drop of water of at least about 55 degrees.
 26. The coatedarticle of claim 25, wherein said hydrophobic coating system furthercomprises at least one fluoro-alkyl silane (FAS) compound.
 27. Thecoated article of claim 25, wherein said hydrophobic coating systemincludes first and second DLC inclusive layers of different hardnesses,wherein said second DLC inclusive layer is harder than said first DLCinclusive layer and said first DLC inclusive layer is located betweensaid second DLC inclusive layer and said IR reflecting layer.
 28. Thecoated article of claim 27, wherein said first DLC inclusive layerincludes more Si than said second DLC inclusive layer.
 29. The articleof claim 25, wherein said initial contact angle is at least about 80degrees.
 30. A method of making a coated article, the method comprisingthe steps of: providing a substrate; depositing a low-E layerarrangement including at least one IR reflecting layer on the substrate;depositing a DLC inclusive layer on the substrate over the low-E layerarrangement in a manner such that the substrate and the IR reflectinglayer are maintained at temperature(s) no greater than about 200 degreesC. during said depositing of the DLC inclusive layer.
 31. The method ofclaim 30, wherein said depositing the DLC inclusive layer on thesubstrate over the low-E layer arrangement is performed in a manner suchthat the substrate and the IR reflecting layer are maintained attemperature(s) no greater than about 125 degrees C. during saiddepositing of the DLC inclusive layer.
 32. The method of claim 31,wherein said depositing the DLC inclusive layer on the substrate overthe low-E layer arrangement is performed in a manner such that thesubstrate and the IR reflecting layer are maintained at temperature(s)no greater than about 75 degrees C. during said depositing of the DLCinclusive layer.
 33. The method of claim 32, wherein said depositing theDLC inclusive layer on the substrate over the low-E layer arrangement isperformed in a manner such that the substrate and the IR reflectinglayer are maintained at temperature(s) no greater than about 40 degreesC. during said depositing of the DLC inclusive layer.
 34. The method ofclaim 30, wherein said step of depositing the DLC inclusive layer on thesubstrate comprises using an ion beam deposition source to deposit theDLC inclusive layer on the substrate over the IR reflecting layer. 35.The method of claim 30, wherein said step of depositing the low-E layerarrangement including at least one IR reflecting layer on the substratecomprises sputter coating the IR reflecting layer on the substrate usingat least one appropriate target in the sputter coater.
 36. The method ofclaim 30, further comprising: using a first gas including silicon (Si)in said depositing step for depositing the DLC inclusive layer, whereinthe DLC inclusive layer is a first DLC inclusive layer; and depositing asecond DLC inclusive layer on the substrate over the first DLC inclusivelayer using a second gas different than the first gas.
 37. The method ofclaim 36, further comprising: applying a FAS inclusive layer over thesecond DLC inclusive layer; and depositing the second DLC inclusivelayer in a manner so as to include ta-C, and applying the FAS inclusivelayer in a manner so that the resulting article has an initial contactangle θ of at least about 80 degrees.
 38. The method of claim 36,wherein the first gas includes a silane compound and the second gasincludes a hydrocarbon.
 39. The method of claim 38, wherein the firstgas comprises at least one of tetramethylsilane, trimethyldisilane,tetraethoxysilane, hexamethyldisiloxane, and dichlorodimethylsilane. 40.The method of claim 38, wherein the second gas comprises C₂H₂.
 41. Themethod of claim 36, further comprising the step of depositing the firstand second DLC inclusive layers in a manner such that the first DLCinclusive layer includes substantially more Si than the second DLCinclusive layer.
 42. A coated article comprising: a substrate; a low-Elayer arrangement provided on said substrate, the low-E layerarrangement including at least one infrared (IR) reflecting layer; and aprotective diamond-like carbon (DLC) inclusive layer includingtetrahedral amorphous carbon (ta-C) provided in a position such thatsaid IR reflecting layer is located between said substrate and saidprotective DLC inclusive layer.
 43. A coated article comprising: asubstrate; a low-E coating system provided on said substrate, said low-Ecoating system including at least one infrared (IR) reflecting layer,first and second Si inclusive dielectric layers, and a protectivesubstantially non-crystalline diamond-like carbon (DLC) inclusive layer;and wherein said first Si inclusive dielectric layer is located betweensaid DLC inclusive layer and said IR reflecting layer.